1968 CB77 Upgrade

[flyin_]

Hi everyone. I've been lurking around here for a while so I thought I would introduce myself and add some info on my winter project. Last year I got a great looking 68 CB77 for a great price. I was able to give a quick tune up per the bill silvers guide and put a few hundred miles on it this summer. It ran pretty good but proved to be very finicky and a bit hard to ride. So I knew there would be a few projects to do this winter.

Cosmetically the bike looks great and needs very little. However, the more I rode it, the less confident I became with the mechanical side of it. By the end of this summer I finally admitted that I might just have a bimbo...great too look at but lacking in performance.

Our relationship started off a little rocky, not unlike a few of my other vintage love affairs. For starters, she almost killed me on our maiden freeway voyage. I was having a great time blasting down I35 past downtown Minneapolis when I entered a fast left hand corner in the left lane...while leaning into the corner the bike stopped leaning and started making terrible noises. The next thing I knew I was in the right lane and then stopped on the shoulder. The side stand had come down and I wrestled the bike through the corner flat on the stand at 65 miles per hour. I still don’t know how I got myself out of that one. I do remember seeing the shocked faces in the first few drivers to pass me when I got on the shoulder.

Anyway, this winter I will be rebuilding/replacing the transmission, repairing the broken right side cover at the kick start, sorting out the electric starter, and a few other odds and ends. I hope to document the process of rebuilding the transmission and crossing 2nd and 3rd gears, and replacing the bronze bushing in the right side cover.

I’ll get some pics up as soon as I can.

Ryan

[flyin_]

Here are a few pics

[Superchicken]

Nice bike, welcome the forum, lots of good info here. Your forks and seat mean it is earlier than 68. Good score!! Having the center stand drop down around a curve, must have gotten your full attention, ha?

[Goodysnap]

Ryan ,

Glad to hear that I'm no the only one that's happened to. You are not alone. New return spring should take care of that. Not a pleasant experience in the least. Nice looking bike. Welcome to the forum and keep us up to speed on your progress. Loads of help and information here.

Brent

[flyin_]

Here is a photo of the bottom of the side stand after the incident. I think the mounting plate was bent which might have caused the issue...this also allowed the bike to lean over much farther increasing the excitement. There will never be a side stand on this bike again!

[flyin_]

One of the most obvious issues with the bike was a wobbly kick starter. Why would they ever put a plastic bushing to support a stubby kick shaft.

After removal of the side cover I could see the cover was broken around the bushing allowing the excess play at the shaft. The old bushing was easily removed by putting a metal washer over the bushing and gently tapping towards the broken side of the cover with a hammer and a brass punch.

I am going to get some bronze bearing stock and have a new bushing machined to fit. I'll repair the broken cover with JB weld. I think this would be a worthwhile upgrade for everyone.

[flyin_]

The main reason for this winter overhaul was transmission issues. In 1st gear when powering on the bike seemed to shift, or pull in a weird way. Almost like the engine was being torqued sideways in the frame. Don't know how else to describe it. And in 2nd gear it tried to jump out of gear. It never actually jumped out but the surge/jump made riding around town difficult. It always felt like it was about to blow up. 3rd and 4th gears felt great and riding on the highway was no problem.

I have been trying to get a little more info on crossing 2nd and 3rd gears. I think this would definitely help out around town. Hopefully someone who has done this will be willing to help me out on that one.

When I got the engine cases split the problems were obvious. The bushing at 1st gear on the counter shaft is shot allowing the gear to wobble a couple mm on the shaft. And the gear dogs on 2nd gear only engaged by about 10% of their area.

Luckily I was able to get a used transmission with the shift drum on ebay for a good price. The transmission looks like it has hardly been used. I am going to swap out the whole assembly.